Unloader for wicket-type conveyers



Aug. 11, 1953 w. l.. BEST x-:T AL

UNLOADER FOR wcxT-TYPE coNvEYERs 2' sheets-sheet 1 Filed NOV. 26, 1949 INVENToRs BY 0m72.445s H.L15cH,J/a.

A TTG/ENE YO v2 Sheets-sheet 2 Aug. 1l, 1953 w. 1 BEST ETAL UNLQAQER FOR wIcKET-TYPE coNvEYERs 'Filed Nov. 26, 1949 1NVENToR5 WILL/AM L. BEST'QND BY cfm/:Les HJJSCHJR.

(M01/LA 9 Patented Aug. 1l, 1953 UNLOADER FOR WICKET-TYPE CONVEYERS William L. Best, Detroit, and Charles H. Lisch, .I r., Grosse Pointe Woods, Mich., assignors to Young Brothers Company, Detroit, Mich., a corporation of Michigan Application November 26, 1949, Serial No. 129,656

14 Claims. 1

This invention relates as indicated to unloaders for conveyors, and more particularly to unloaders for conveyors having racks or carriers of the wicket type.

In the heat processing of thin, flat sheets, such as lithographie plates, is customary practice to transport the sheets through an oven on a conveyor, the respective courses of which lie one above the other, having a plurality of outwardly extending, closely spaced racks therealong for 4supporting the sheets on edge. A typical example of -this type conveyor is shown in Patent No. 2,- 406,821, issued to V. A. Fox under date of September 3, 1946. As the racks pass over the work discharging end of the conveyor, the sheets car- 'ried thereon are deposited flatwise on a moving take-off belt for removal therefrom. However, vat that point the racks are moving in a downwardly direction and impart little or no forward velocity to the sheets. Further, since the sheets are supported on edge in rather close relation on the rack conveyor, and are then deposited natwise on the take-off belt, it will be appreciated that the latter will necessarily be run at a much lgreater Vspeed than the rack conveyor.

As aresult of the relatively high speed of the 'take-off lbelt and the fact that the sheets have no 'appreciable forward velocity at the instant of y.contact with the belt, there will be considerable lslippage before the sheets begin to move with the latter. Not only may such slippage result in `damaging or marring of the sheets, but it has 'the further effect of delaying the removal of each sheet from the path of the next succeeding rack and'thereby slowing down the conveyor operation. Additionally, differential slippage may Icause the sheets to be turned askew as they contact the take-off belt or belts, making later handling awkward.

A vprimary object 'of this invention is accord- A`ingly to provide unloading means for a wickettype conveyor which will permit rapid operation 'of such conveyor and eliminate slippage between work-pieces and a rapidly travelling take-off belt 'or the like.

` A further object is to provide positive means operative -to provide an initial impetus to the work-pieces in a new direction as they are deposited by such conveyor on continuously travelling take-off means.

Other objects and advantages of the invention will appear as the description proceeds. To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following descri'ption and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being' indicative, however7 of but Ya few of the various ways in which the principle Vof the invention may be employed.

In said annexed drawing:

Fig. 1 is a top plan View of the work discharging end of a conveyor showing an unloader device and a portion of a take-off belt illustrating one embodiment of my invention;

Fig. 2 is a sectional view taken along the line 2 2 on Fig. 1; and

Fig. 3 is a detail side elevational View of a cam forming an element of the unloader mechanism.

Apparatus suitable for use in connection with the drying of lithographie plates has been provided as one preferred embodiment of this invention, including an endless conveyor, the respective courses of which are located one above the other. Wicket-type rack members are arranged on the conveyor in closely spaced relation for supporting the plates on edge. Provided at the work discharging end of the conveyor and arranged in tandem therewith are a plurality of endless belts to receive and carry away the plates deposited thereon. A pair of pushers are positioned at the work discharging end of the conveyor adapted to be reciprocated longitudinally thereof, and cam means are provided thus to reciprocate the pushers in timed relation to the 'travel of the conveyor to engage each plate deposited on the belts and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which the belts are travelling, whereby initial slippage between belts and plates is obviated.

Referring now to the drawing and more especially to Figs. 1 and 2 thereof, the apparatus to which this invention relates includes a conveyor which may comprise parallel courses of endless chains I engaging sprockets 2 secured to shaft 3, such shaft 3 being mounted in pillow blocks 4, secured to channels 5 by means of bolts t. The shaft 3 is provided with a gear 'i keyed to the end thereof which is driven by a worm gear 8, the latter in turn being driven by a chain upon a sprocket It! carried by the longitudinally extending shaft l I. An electric motor, not shown in the drawing, may be provided to drive .the shaft l! in conventional manner. Provided at intervals along the conveyor are a plurality of closely spaced racks i2 which are inclined opposite to the direction of travel of the upper conveyor course and on which the sheets are carried. The racks are of the wicket-type and consist of open frames having flanges or lips i3 at the bottom thereof for supporting the sheets on edge.

Located at the work discharging end of the conveyor and arranged in tandem therewith are endless take-off belts It, 5, I6, il and It which are provided for removing the sheets from their respective racks. The belts l I5 and l5 are carried respectively by pulleys I9, 20 and 2| mounted on brackets 22, 23 and 24 bolted to the transverse channel 25. The belts Il and I8 are carried by pulleys 26 and 21 respectively, mounted on columns 28 and 29, likewise bolted to the transverse channel 25. The chain 30 driven by sprocket 3| of the shaft 3 is provided to actuate all of the belts. The frame work forming the upper boundary of each rack is `shaped with a V-shaped notch o1' indentation 3-2 therein so that the racks may p-ass the belt I5 and its pulley and bracket without interference therewith. Thus, as each rack passes the work discharging end of the conveyor, the sheet carried thereon is deposited on moving belts I4, I5 and I6 and quickly removed from the path of the next' suc-r ceeding rack, belts I1 and I8 assisting in this action as soon as the sheetis moved into contact with the same. Where the. sheets are not of sufficient width to contact the belts |14r and I6, they are deposited on the central belt |15 only which extends into the notch 3-2 of the rack frames, lateralA support being.v provided by the rollers 33 until the sheets are moved into contact with the belts I=1' and I8. The rollers 33 are mounted on brackets 341 bolted: respectively to thev columns 28 and 29 and are: progressively increasingly laterally spaced to the extent permitted by the generally V-shaped notch 32 in the Work-supporting racks.

Positioned at the unloading. en'd of. the conveyor is a pair of laterally spaced kickers or pushersv 3'5" which are adapted. to reciprocate longitudinallyv of the conveyor, thereby tol give an initial forward velocity or impetus tov the sheets as the latter come in contact with the take-off belts. There will be no interference be'- tween the pushers and' the racksl since, as illustrated in Fig. I, ample clearance is provided by the notched recesses. 36l in the base' of the racks to permit. the reciprocation of the pushers. Each respective pusher is secured to one end of a connector 31 by means of bolts 38, such. connector being secured at itsA other end to push4 rod 39V by means of set screws 401. Each push rod 39y .is reciprocably mounted ina pusher bearing guide 4Iv weldedr to a boss 42V secured to the transverse channel 43 by means of bolts 44, such channel being secured to`l the columns 45 as by means of bolts or welding.

The reciprocating motion of. the pusher 35 is controlled by a groove follower' cam 46 which is keyed on one end of a cam shaft 41 and secured thereon by nut 48', such shaft being located between the respective courses of the conveyor transversely thereof and mounted in pillow blocks 49 bolted to the channel 50'. The channel 50 is bolted to the transverse channels 5I, such latter channels being bolted to the longitudinal channels 5'2. Likewise located between the courses of the conveyor andparallel to the cam shaft 41 is a cam follower shaftY 53 mounted in pillow blocks 54 bolted to the channel 56. A rocker arm 55 is keyed to the central portion of the cam follower shaft 53, and pivotally mounted at the end of the arm 55 is a roller cam follower 56 whichv is adapted to engage the cam track or groove 51 of thecam 46.

Likewise keyed to the cam follower shaft 53 are upwardly extending rocker arms 58 and' to the end of each such arm is pivotally secured a snap connector 59'. Similarly mounted on the end of eachy push rod 39 is a snap connector 60. The corresponding push rods 391 and arms 58 are connected together by means of connecting rods 6I. Each connecting rod 6I passes through the externally projecting portion of a snap connector 59 of an arm 53 and' likewise through a snap connector 6D of the corresponding push nod 39 and is adjustably secured in each` such'- snap connector by means of set screws 62 and 63. Thus, as the cam 46 rotates, raising and lowering the cam follower 56, arm.55 is caused to oscillate, thereby imparting a rocking action to the cam follower shaft 53. Such rocking action is transmitted to the pushers 35 in the form of a reciprocating motionV by'means of the linkages hereinabove described'. As shown in Fig. 3 of the drawing, the contour of the cam. track 51 between the points 64 and 65 is designed so as to suddenly lift the cam follower 56 as the latter rides in that p0rtion of the cam track, thereby imparting a forward thrust to thepushers.. The cam 46: is rotated in timed relationr withtheconveyor, in a manner hereinafter described, so that the pushers are thrust forward as each sheet is deposited on the: moving take-off belt and quickly retracted to avoid obstructing. the next following sheet,

Keyed to the other end of the carnshaft 41 is abevel gea-r 66 which. is adapted to: mesh. with a second bevel gear 61, suchlattei'. gear being keyed. to counter shaft 69. The: counter shaft $8 is mounted in pillow blocks 63 bolted to the channel 5I] and. has keyed tothe end thereof a sprocket 10 which is? adapted toy be driven. by chain 1I. TheI chain 1-I is in. turn driven by a vsprocket 12 upon the: shaft II, which shaft likewise actua-tes the shaft 3 of the conveyor it in a manner hereinbefore described..

In operation, the conveyor,moving for example through a. heat processingy oven, carriesy sheet material on racksv along its upper course. These racks are inclined opposite toi the direction of conveyor travel until they reach the work. discharging end of. the conveyor, whereupon they tilt forward, as shown in Fig. 2 of. the` drawing, causing the sheets thereon to shi-ft tothe trailing side of the next preceding rack... As. the racks pass' down over the work discharging end of the conveyor, and pass belts I4-, I5 and I-6,.the sheets thereon are deposited` on such. belts (narrower sheets being. deposited on the central beltv I5 only) a-nd on rollers 33.. The cam 46, which is rotated in timedrelationwith: the conveyor travel, is designed to impart a forward( stroke to the pushers as each sheet contacts` the bel-ts, enga;- ing the inner edges of suchsheetsand.. giving. them an initial forward velocity so thatthey are moving with the belts at the instant of Contact.y The velocity of the forward stroke of the pushers. depends on the design of the cam, and should be such that it will impart a velocity to the sheets which is substantially equal to( the' velocity of travel of the belts, so that no slippage will result when the sheets come irrr contactl with the latter. It will. be appreciated that, where such a conveyor is employed to tran-sport lithographic plates through a dryingoven',l such plates will likely be deposited upon. thebelts face downward (having preferably been loaded face upward at the work entering end of the' oven) sov that slippage might mar the same.

Once the cam is adjusted to function in harmony with the. conveyor, i. e. to impart a forward stroke to the pushers as each sheet is deposited on the belts, synchronization is obtained. for all speeds of the conveyor since both the cam: and. the conveyor are actuated' by the shaft I I-. Similarly, since the take-off belts are driven by the conveyor, the speed of the belts will at all times be proportional to the speed of the latter.

By giving. the sheets apush in the direction of travel of the'- beltsat the instant of. contact,- it

will be seen that the unloader device of this invention not only obviates initial slippage and the damage and marring attendant thereto, but also implements the removal of the sheets from the conveyor racks, permitting speedier conveyor operation.

Since it is a characteristic of a groove follower cam such as the one employed in this embodiment that the outer edge of the groove tends to turn the cam follower in one direction while the inner edge of the groove tends to turn it in the other, suflicient clearance or play should be provided between the groove and the cam follower in order that wear on such respective members may be kept at a minimum.

It will be understood that the form of work supporting racks or wickets may be varied considerably and may, for example, comprise transverse alignments of erect fingers carried by two or more parallel conveyor courses, all as is well known in the art. Since such ngers need not be laterally7 interconnected the problem of introducing the work transfer pusher means therebetween is eliminated as well as permitting extension of the take-off conveyor belts,

Although the unloader device herein described has been indicated as being serviceable in connection with the drying of lithographie plates, it is clear that it has a wider field of use and may be used wherever it is desired to transfer workpieces from one conveyor to another, or quickly to discharge work-pieces from the racks of a wicket-type conveyor. Further, although the sheet material transported will generally be flat, clearly the unloader device is equally useful for material of other conformations where all portions of such material do not lie in the same plane. It should also be kept in mind that the scope of this invention is not limited to such cam means as is herein described, but that any suitable device, as, for example, a Scotch-yoke may be utilized to impart a reciprocating motion to the pushers. Certain subject-matter disclosed but not claimed herein is disclosed and claimed in co-pending application Serial No. 133,172 of Charles H. Lisch, Jr., and Frank Schuman iled December 15, 1949, now Patent No. 2,552,101.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

l. The combination of an endless conveyor, having courses lying one above the other, wickettype racks carried thereby in closely spaced relation for supporting sheet material on edge, an endless travelling take-,olf belt located at the work discharging end of said conveyor and arranged in tandem therewith to receive and carry away such sheet material deposited ilatwise thereon from said respective racks, pusher means positioned at the work discharging end of said conveyor and adapted to be reciprocated longitudinally thereof, means operative to drive said belt| at a speed greater than, and proportional to, the speed of'said conveyor, whereby to accommodate singly the sheets deposited flatwise thereon, and drive'means operative to reciprocate said pusher means in timed relation to the travel of said conveyor to engage each sheet deposited on said belt and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which said belt is travelling, whereby initial slippage between said belt and sheets is obviated,

and then to retract said pusher means from the path of the next succeeding sheet.

2. The combination with an endless conveyor having courses lying one above the other, wickettype racks carried thereby in spaced-apart relation for supporting sheet material on edge, and an endless travelling take-off belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such sheet material deposited thereon from such respective racks; of pusher means positioned at the work discharging end of such conveyor and adapted to be reciprooated longitudinally thereof, and drive means operative thus to reciprocate said pusher means in timed relation to the travel of such conveyor to engage each sheet deposited on such belt and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and sheets is obviated.

3. The combination with an endless conveyor having courses lying one above the other, racks carried thereby in spaced-apart relation for supporting sheet material von edge, and an endless travelling take-olf belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such sheet material deposited thereon from such respective racks; of a pusher positioned at the work discharging end of such conveyor and adapted to be reciprocated longitudinally thereof and into the path of such racks, a recess provided in the base of each such rack to permit the advance of said pusher, and drive means operative thus to reciprocate said pusher in timed relation to the travel of such conveyor to engage each sheet deposited on such belt and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and sheets is obviated.

4. The combination with an endless conveyor having courses lying one above the other, wickettype racks carried thereby in spaced-apart relation for supporting sheet material on edge, and an endless travelling take-oir0 belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such sheet material deposited thereon from such respective racks; of two pushers positioned at the work discharging end of such conveyor and adapted to be reciprocated longitudinally thereof and into the path of such racks, recesses provided in the base of each such rack to permit the aclvance of said pushers, a recess in the outer portion of each such rack to permit the protrusion therein of such belt, and drive means operative thus to reciprocate said pusher means in timed relation to the travel of such conveyor to engage each sheet deposited on such belt at the instant of contact therewith and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and sheets is obviated.

5. The combination with an endless conveyor, racks carried thereby in spaced-apart relation for supporting work-pieces, and an endless travelling take-olf belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such work-pieces deposited thereon from such respective racks; of pusher means positioned at the work discharging end of such conveyor and adapted to be reciprocated longitudinally thereof,

ama-12e and drive means. operative thus to reciprocate said pusher meansin timed relation to the. travel of such conveyor to engage eachwork-piece deposited onsuch belt and impart a velocity thereto substantially equal in magnitude and. direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and work-pieces is obvia-ted.

6. The combination with an endless conveyor adapted to carry work-pieces thereon, and an endless travelling take-off belt located at, the work discharging end of such conveyor arranged in tandeml therewith to receive and carry away such work-pieces deposited thereon from such conveyor; of pusher means positioned at the work discharging end of such conveyor and adapted to be reciprocated' longitudinally thereof, and drive means operative thus to reciprocate saidpusher means in timed relation to the-travel of. such conveyor to engage each work-piece deposited on such belt and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and work pieces is obviated.

'7. In combination with an endless conveyor, racks carried thereby in spaced-apart relation for supporting work-pieces, and. an endless travelling take-off belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such work-pieces deposited thereon from such respective racks; reciprocable pusher means positioned at the work discharging end of such conveyor` operative in timed relation to the travel of such conveyor to engage each work-piece deposited on such belt and impart a velocity' thereto substantially equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and worlipieces is obviated.

8. In combination with an endless conveyor adapted to carry work-pieces thereon, and an endless travelling take-ofi belt located at the work discharging end of such conveyor arranged in tandem therewith to receive and carry away such work-pieces deposited thereon from such conveyor; pusher means positioned intermediate such conveyor and belt operative in timed relation to the travel of such conveyor to engage each work-piece deposited on such belt and impart a velocity thereto substantiallyv equal in magnitude and direction to the velocity at which such belt is travelling, whereby initial slippage between such belt and work-pieces is obviated.

9. In combination, two conveyors arranged in tandem and travelling in the same direction, work supporting means carried by one of said vconveyors operative to transfer work-pieces directly from one conveyor to the other, and pusher means intermediate said two conveyors operative to engage the work-pieces at the point of transfer and impel the same in the direction of the receiving conveyor 10. In combination, a conveyor having racks for supporting generally flat work-pieces thereon in closely spaced relation, a second conveyor travelling at a greater speed in the same direction and arranged in tandem to directly receive workpieces from said rst conveyor, and pusher means reciprocable in timed relation to the travel of said rst conveyor and disposed to engage such work-pieces and impel them flatwise in the direction of travel oi said second conveyor for renio-Val by the latter in. spaced relation thereon.

11,. In combination, an endless. conveyor having upper and lower courses and comprising spaced parallel, runs laterally connected by upstanding racks adapted to support generally at work-pieces on edge in such upper course, ay second conveyor arranged in tandem with said first conveyor and travelling at a greater speed in the same direction, said second conveyor lying inra generally horizontal plane successively in alignment with each of such racks. as the latter pass from the upper to the lower course. of said rst conveyor whereby the work-pieces will be directly deposited flatwise on such second conveyor, and pusher means reciprocable in timed relation to the travel of said vfirst conveyor adapted to ad- Vance between such runs and enga-ge and impel such work-pieces in the direction of travelof said second conveyor.

12. In combination, a conveyor adapted to transport generally flat work-pieces in closely spaced relation Iiatwise to the directionof travel, a second conveyor in close association with said first conveyor to directly receive work-pieces therefrom and travelling in a direction generally normal to the direction of travelof said first conveyor at such point of close association, said second conveyor being adapted to: transport lsuch work-pieces edgewise to the direction of travel, and pusher means positioned intermediate said conveyors operative in timed relation to. the travel of said rst conveyor to engage such Workpieces thereon at the point of closest association with said second conveyor and impel the same in the direction of movement oi said second conveyor, thereby to assist in transferring the same.

13. In combination, an endless conveyor adapted to carry Work-pieces thereonl a plurality of endless take-ofi belts arranged in tandem with said conveyor and unequally spaced therefrom to directly receive and carry away such workpieces, and pusher means intermediate such conveyor and belts operative in timed relation to engage each work-piece as it is transferred to such belts and impart a velocity thereto substantially equal in magnitude and direction to the velocity at which such belts are travelling, whereby initial slippage between such belts and workpieces is obviated,

14. In combination, an endless conveyor having transverse racks for supporting work-pieces, a second conveyor located at the work discharging end of said first conveyor in overlapped relation therewith, whereby work-pieces supported on such rst conveyor will be directly deposited `on such second conveyor, and pusher means intermediate such conveyorsv operative to engage each work-piece thus deposited and positively impel the same in the direction of said second conveyor.

WILLIAM L. BEST. CHARLES H. LISCH, JR.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 648,684 Davis May 1, 1900 1,288,810 Birchbauer Dec, 24, 1918 1,306,573 Bevier June 10, 1919 1,753,998 Podel Apr. 8, 1930 2,100,441 Greene Nov. 30, 1937 

